1. Field of the Invention
This invention relates to a system and method for automatically extinguishing or controlling a fire which is burning in a prescribed area.
2. Background Art
In many environments, systems have been designed for automatically extinguishing or controlling a fire that may be inadvertently started. One such system will be described below with respect to an exemplary environment.
As shown in FIG. 1, a system for extinguishing a fire is shown at 10 in association with a machine tool 12, which may have any of a multitude of different constructions and capabilities. The machine tool 12 operates in a prescribed area in which a fire may be inadvertently started during normal machining operations. Typically, rooms in which the machine tool 12 is operated utilize venting systems 14 which direct oil, water particles, and other matter entrained in the air within a machining space, to an appropriate location for collection or discharge. The venting system 14, while enhancing the environment around the machine tool 12 for human occupation, also vents the region around the machine tool 12 so as to contribute to the spread of any fire that may have started.
The function of the system 10 is threefold. First, the system 10 causes an extinguishing substance, in this case shown as CO2 contained at a source 16, to be directed at the fire. Secondly, the system 10 closes the venting system 14 so as not to facilitate fire propagation. Finally, the system 10 causes the machine tool 12 to be shut down.
To effect the above three functions, one conventional system utilizes a sensor 18 to detect the presence of smoke or fire. The sensor 18 may take any of myriad different forms known to those skilled in the art. Upon detecting either smoke or fire, the sensor 18 sends a signal to a central controller 20, which coordinates operation of the machine tool 12, the venting system 14, and a valve 22, which selectively releases the CO2 from the source 16. The controller 20 effects shutdown of the machine tool 12 and venting system 14, and operates the valve 22, through an electrical circuit 24.
While systems, such as that shown at 10 in FIG. 1, have been generally effective, systems of this type that rely on electrical circuitry may be prone to malfunction by reason of either their complexity or their sensitivity to heat or contamination generated during a fire. The machine tool industry, as well as other industries, is constantly seeking new and better ways to control inadvertently started fires in this type of environment.
In one form, the invention is directed to a system for extinguishing a fire. The system has a source of a substance which is usable to extinguish or control a fire in a prescribed area, a control system, and an activation system. The control system has (a) a first state in which the substance from the source is prevented from being released to the prescribed area and (b) a second state wherein the substance from the source is permitted to be released to the prescribed area to extinguish or control a fire at or adjacent to the prescribed area. The activation system has a first ignition element which ignites in response to exposure to at least one of (a) a flame, (b) heat above a predetermined temperature, and (c) a product of combustion. The control system is changeable from the first state into the second state an incident of the ignition element being ignited.
In one form, there is no electrical circuitry which is responsible for changing the control system from the first state into the second state.
In one form, the control system consists of a pressure responsive switch which changes from a normal state into an activated state as an incident of the first ignition element being ignited. The control system is in the first state with the pressure responsive switch in the normal state and in the second state with the pressure responsive switch in the activated state.
In one form, there is a conduit which has a passageway in which pressure is generated in response to ignition of the first ignition element and which causes the pressure responsive switch to change from the normal state into the activated state.
A shutoff may be provided for selectively blocking the passageway between the first ignition element and pressure responsive switch to disable the activation system.
The system may further include a second ignition element which is ignited as an incident of the first ignition element being ignited.
The ignition of the second ignition element causes the control system to change from the first state into the second state.
In one form, the substance used to extinguish or control the fire is CO2.
The system may include an operable system component in addition to the control system and having an operating state and a disabled state, a deactivation system, and a second ignition element which is ignited in response to ignition of the first ignition element to cause the deactivation system to change from a normal state into a deactivation state. The operable system component changes from the operating state into the disabled state as an incident of the deactivation system changing form the normal state into the deactivation state. This same function may be effected without the requirement for the second ignition element.
In one form, the operable system component is one of a machine tool and a venting system for atmospheric air in the vicinity of the prescribed area.
The venting system may have an associated damper which is changeable between open and closed states. The damper is in the open state with the venting system in the operating state and in the closed state with the venting system in the disabled state.
The ignition element may include an explosive component.
The invention is also directed to a method of extinguishing a fire in a prescribed area. The method includes the steps of: situating a first ignition element in the vicinity of the prescribed area; in response to exposure of the first ignition element to at least of (a) a flame, (b) heat above a predetermined temperature, and (c) a product of combustion, causing the first ignition element to ignite; and in response to ignition of the first ignition element causing a control system to release a substance from a source of the substance to the prescribed area to extinguish or control a fire in the prescribed area.
The method may further include the step of changing an operable system component in addition to the control system from an operating state into a disabled state in response to ignition of the first ignition element.
The operable system component may be one of (a) a machine tool for performing a processing operation on a workpiece and (b) a venting system for atmospheric air in the vicinity of the prescribed area.
The method may further include the step of causing the first ignition element to ignite a second ignition element. The ignition of the second ignition element causes the control system to release the substance to the prescribed area to extinguish or control a fire in the prescribed area.
The first ignition element may ignite a second ignition element so that the second ignition element causes the operable system component to change from the operating state into the disabled state.
The first ignition element may include an explosive component.
The substance used to extinguish or control the fire may be CO2.